[PATCH] kexec jump: fix compiling warning on xchg(&kexec_lock, 0) in kernel_kexec()
Eric W. Biederman
ebiederm at xmission.com
Wed Aug 13 14:12:48 EDT 2008
Linus Torvalds <torvalds at linux-foundation.org> writes:
> On Wed, 13 Aug 2008, Huang Ying wrote:
>>
>> - xchg(&kexec_lock, 0);
>> + locked = xchg(&kexec_lock, 0);
>> + BUG_ON(!locked);
>
> Why do you want to do this at all?
>
> And why do you implement your locks with xchg() in the first place? That's
> total and utter crap.
>
> Hint: we have _real_ locking primitives in the kernel.
This part certainly.
The way the code should work, and the way it has in the past is:
image = xchg(&kexec_image, NULL)
if (!image)
return -EINVAL;
Very simple and very obvious and very easy to get right, and it has
been that way for years.
Eric
More information about the kexec
mailing list